Sliding doors for industrial applications are well known. For example, for a large scale industrial freezer, in which forklift trucks are continually coming in and out of the freezer, insulated sliding doors have been used. The sliding doors are typically suspended by trolleys that have wheels engaged on tracks which are mounted to the wall over the doorway. There may also be tracks on the walls at the bottom of the door to hold the bottom of the door close to the doorway. Two panels are typically provided which meet in the middle of the doorway and are operated by a belt which is power driven at the top of the doorway and has a lower run of the belt attached to one of the panels and an upper run of the belt attached to the other panel, so that when the belt is driven, the panels move away from one another to open the doorway. When the belt is driven in the other direction, the panels move together toward one another to close the doorway. The opening of the door is typically actuated by a motion detector, a pull cord connected to a switch or an induction loop in the floor that senses the presence of a vehicle. Although the sliding doors open and close with considerable speed, the forklifts also travel with considerable speed. Sometimes, when a door is opening or closing, the forklift may impact the door, usually adjacent to a leading edge of one of the door panels. When this happens, severe damage can occur to the door.
Prior art doors made to endure impacts such as this have typically been made of fabric covered foam or other soft materials, which can absorb impact without significant damage to the door. However, the materials of these doors have other disadvantages, including that they wear out, the severity of the impact that can be endured is quite limited, they are not easily cleaned, they absorb moisture, they can contribute to mold growth which is important in a food storage facility, and they can become torn, and do not present a structural or aesthetic appearance.